“Although we saw strong growth across all categories, the performance of our premium Specially Selected range in particular surpassed all expectations.”

Aldi said it was increasing the minimum hourly rate of pay for store assistants to £8.85 nationally, a 3.75% rise, and £10.20 in London, a 4.6% boost, from 1 February.

The company, which also pays employees for breaks unlike some chains, claimed it was reaffirming its position as the UK’s highest-paying supermarket.

The rates match the independently verified living wage recommended by the Living Wage Foundation, but Aldi is not formally accredited to the scheme as not all its workers are guaranteed the rate as a minimum.

Aldi’s performance suggests another strong year for the discounters, putting further pressure on the major supermarkets. Bruno Monteyne, an analyst at Bernstein Research, said 10% of Aldi’s growth came from new store launches and another 2.5% was the result of price inflation.

He said Aldi’s profit margins were likely to come under pressure as chains such as Tesco, Sainsbury’s and Asda reduced prices amid rising costs.

Convenience stores are also thought to have taken business from the supermarkets towards the end of 2017, partly because they benefited from being allowed to open for longer on Sundays, including Christmas Eve.

Grocery wholesaler Nisa, which serves thousands of independent corner shops, said its sales had risen 1.7% at established stores in the 10 weeks to New Years Eve. The Co-op’s sales rose 6.2% at established stores in the two weeks to 1 January.